Ultrasonic cleaners or ultrasonic baths are electrical devices that remove impurities from surface of hard objects by means of cavitation.
Operating principle of ultrasonic cleaners
Cavitation is process of rapid formation and collapse of small bubbles in the liquid, under influence of ultrasound waves passing through liquid in ultrasonic cleaners. Cavitation occurs because of alteration of high and low pressure waves generated by ultrasound transducers. During the phase of low pressure bubbles are forming and enlarging until the moment when high pressure wave comes. Then they shrink and implode. When implosion occurs, shock waves are form that carry large amount of localized energy. This energy overpowers adhesion force that holds impurities stuck to surface of contaminated items, resulting in their removal from the surface. Small size of bubbles enables them to penetrate cracks, holes, pores, perforations and undulations that are hard to reach when cleaning manually.
Built of ultrasonic cleaners
Main elements of ultrasonic cleaner are cleaning tank, ultrasonic transducers and electronics that control transducers. Often, but not always, ultrasonic cleaners can have tank heaters, discharge valves and other parts that make their use easier.
Cleaning tanks are made from SUS 304 stainless steel of different thickness. Thicker tanks provide for longer lifetime of appliance, and can withstand longer cleaning cycles. Seamless panel housing is especially relevant as it prevents water leakage and moisture from access to electronics inside of units.
Cleaners have industrial high Q transducers which ensure strong power of ultrasonic effect. Ultrasonic transducers emit waves at frequency of 28 – 120 kHz into cleaning tank. No screw welding technology of ultrasonic transducers ensures smooth bottom of the tank, thus improving cavitation and reducing corrosion of the tank. Also, transfer of ultrasonic waves to liquid in tank is much smoother and without interference.
Ultrasonic transducers are activated by independent excitation ultrasonic generator (PWM control), which has passed 4200V HV test and HV isolation test, therefore enabling cleaners to work with stable ultrasonic effect and run safely. Display/control PCBs at front of the ultrasonic cleaner casing are giving input to the generators to determine performance of ultrasonic transducers.
Tanks of ASonic cleaners have heating via MCH heating chips. There is minor difference between the real water temperature and the panel readout which in ±1°C range.
How to use ultrasonic cleaners
Use of ultrasonic cleaners is very simple. Place the device on a firm surface and put cleaning basket with items for cleaning into tank. Fill the tank with liquid so that all items in basket are submerged. In order to achieve better results, you can use ultrasonic cleaning concentrate, depending on impurities and items that need cleaning. Connect ultrasonic cleaner to power grid and turn it on. Set desired cleaning temperature (usually 40-50°C) and wait for liquid in the tank to heat up. Once temperature is achieved, set timer according to the needs of cleaning process and activate ultrasound. When cleaning is complete, wait for the liquid in cleaner to cool down and remove items from the reservoir. Rinse the items after cleaning. Use dry cloth to wipe the tank.
Application of ultrasonic cleaners
Various materials can withstand cleaning in ultrasonic cleaners, such as metals, alloys, plastic, glass, ceramic, rubber. Items made of these materials, such as jewelry, laboratory vessels and instruments, bearings, mechanical elements, carburetors, razor heads, combs, eyeglasses, dentures, waterproof watches, dental instruments, printed circuit boards and cartridges, parts of weapons (bullet casings, brass parts), toys, bottles, pacifiers, and so on are susceptible for this method of cleaning. Ultrasonic cleaners successfully remove impurities such as dust, oil, grease, rust, scale, pigments, bacteria, blood, algae and etc.
Today ultrasonic cleaners are becoming wide spread as they offer fast and efficient cleaning at an affordable price. Professionals, hobbyists and regular people turn to ultrasonic cleaning as it is easy and safe.